Solution

The correct answer is option 3.

Key Points

Handshaking:

When one computer sends a message to another indicating that it wants to create a contact channel, it is called handshaking.  It requires two control signals working in opposite directions

Programmed I/O:

​​The output of the I/O instructions written in the computer programme is the trigger. It requires the CPU to check the I/O   flag & perform the transfer

Interrupt-initiated I/O:

Interrupt powered I/O is a different way to deal with I/O. Interrupt I/O is a method of monitoring input/output operation by sending a signal from a peripheral or terminal that needs to send or receive data. I/O interface informs the CPU that the device is ready for transfer

I/O processor:

A processor with direct memory access is known as an input-output processor (IOP). The computer system is divided into memory units and processors in this way. I/O processor has local memory & control a large set of I/O devices.

∴ Hence the correct answer is A-II, B - IV, C - I, D - II.